The attachment of Eimeria tenella to its target cells as an obligatory intracellular pathogen is essential for the development of disease. Previous reports have established that other intracellular protozoa parasites have either fibronectin, an adhesion protein, or fibronectin receptors, both of which are involved in the interaction with the host cells. In this current research, studies have been undertaken to visualize a surface component that may be involved in the attachment of E. tenella to host cells. For this purpose, monoclonal antibodies, both anti-chicken and anti-human fibronectin, and also anti-chicken integrin were used. Our results show a fibronectin-like molecule with an apparent molecular weight of 110 kDa in mature schizonts and microgametes. Staining with serum directed against chicken integrin revealed immunoreactivity within mature schizonts. Both the fibronectin-like molecule and the integrin may play an important role in the parasite stage-cell interaction and the promotion of parasite uptake.